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Abstract:

Slip members for use with downhole tools comprise a body formed of a
first or body material and one or more hard material elements formed of a
second or element material. The element material is harder than the body
material. The hard material element is disposed through the body and in
communication with a first surface and a second surface of the body, the
second surface being disposed opposing the first surface. During
manufacturing of the slip members, the hard material element may extend
outwardly from one or both of the first and second surfaces. After
manufacturing, the hard material element can be shaped to provide a
gripping member.

Claims:

1. A slip member comprising: a body, the body comprising a first surface
and a second surface, the body comprising a first material; and a hard
material element disposed through the body in communication with the
first surface and the second surface, the hard material element
comprising a second material, the second material being harder than the
first material.

2. The slip member of claim 1, wherein the hard material element extends
outwardly from the first surface.

3. The slip member of claim 2, wherein the hard material element extends
outwardly from the second surface.

4. The slip member of claim 1, wherein the hard material element extends
outwardly from the second surface.

5. The slip member of claim 1, wherein the hard material element
comprises a polygonal-shaped cross-section.

6. The slip member of claim 1, wherein the hard material element
comprises a bore disposed through the hard material element.

7. The slip member of claim 6, wherein the hard material element
comprises a polygonal-shaped cross-section.

8. The slip member of claim 1, wherein the hard material element is
disposed through the body at an angle relative to a vertical axis of the
slip member, the angle being in the range from 10 degrees to 60 degrees.

9. The slip member of claim 1, wherein the hard material element
comprises a first end, a second end, a first wall surface connecting the
first and second ends, and a second wall surface connecting the first and
second ends, the first wall surface being tapered from the first end to
the second end.

10. The slip member of claim 9, wherein the second wall surface is
tapered from the first end to the second end.

11. The slip member of claim 10, wherein the first end comprises a
gripping member.

12. The slip member of claim 1, wherein the hard material element
comprises a first end, a second end, and a recess disposed around an
outer wall surface, the recess being disposed between the first end and
the second end.

13. The slip member of claim 12, wherein the recess is disposed
approximately half-way between the first end and the second end.

14. The slip member of claim 1, wherein the hard material element
comprises a first portion, a second portion, and a third portion, wherein
the first portion is in communication with the first surface, and the
second and third portions each are in communication with the first
portion and in communication with the second surface.

15. The slip member of claim 1, wherein the hard material element
comprises a first portion, a second portion, and a third portion, wherein
the first portion is in communication with the second surface, and the
second and third portions each are in communication with the first
portion and in communication with the first surface.

16. A method of manufacturing a slip member, the method comprising the
steps of: (a) disposing a hard material element through a wall of a mold,
the hard material element comprising a first material; (b) disposing a
body material in the mold, the body material being softer than the first
material; (c) after a sufficient time has passed for the body material to
set, removing the mold to provide an initial slip-shaped member; and (d)
shaping the initial slip-shaped member into a slip member, the slip
member comprising a first surface and a second surface, and the hard
material element being in communication with the first surface and the
second surface.

17. The method of claim 16, wherein the during steps (a)-(b) the hard
material element extends outwardly from the mold in two directions.

18. The method of claim 16, wherein the during steps (a)-(b) the hard
material element extends outwardly from the mold in at least one
direction.

19. The method of claim 16, wherein step (a) is performed prior to step
(b).

20. The method of claim 16, wherein during step (e) one end of the hard
material element is shaped into a gripping member.

Description:

BACKGROUND

[0001] 1. Field of Invention

[0002] The invention is directed to slip members for securing downhole
tools such as bridge plugs and packers within a wellbore and, in
particular, to slip members comprising one or more hard material elements
disposed through a body material that is softer and, thus, easier to mill
as compared to the hard material element(s).

[0003] 2. Description of Art

[0004] During drilling and production of oil and gas wells, it is
sometimes desirable to isolate zones within the wellbore such as by
disposing downhole tools within the wellbore to seal-off a portion of the
wellbore. Thus, downhole tools such as bridge plugs, packers, and the
like are disposed within the wellbore. To secure the downhole tools
within the wellbore, the downhole tool can comprise one or more slip
members. The slip members include a gripping surface that is forced into
the inner wall of the wellbore. For example, the slip members may include
wickers or other gripping members that are forced into the inner wall of
a casing by sliding the slip member along a cone or ramped surface. After
setting of the downhole tool, additional downhole operations can be
performed.

SUMMARY OF INVENTION

[0005] Broadly, slip members for use in connection with a downhole tool
are disclosed. In one specific embodiment, the slip member comprises one
or more hard material elements comprising a first material disposed
through the slip member, the remainder of the slip member being formed
form a second material. The second material comprises a material that is
softer as compared to the first material. The hard material elements can
be aligned through the slip member either at an angle that is
perpendicular to a vertical axis of the slip member, or at an angle
within the range from 0 degrees to 180 degrees relative to the vertical
axis. In addition, the hard material elements can be hollow and can have
numerous different cross-sections, e.g., circular or polygonal. Further,
the hard material elements can be disposed in dense packs, or spread out
from each other. In one particular embodiment, the hard material elements
extend outward from both a first surface of the slip member and a second
surface of the slip member, the second surface being disposed opposite
the first surface, during construction so that the slip member can be
manufactured with either the first surface comprising the gripping
surface or the second surface comprising the gripping surface.

BRIEF DESCRIPTION OF DRAWINGS

[0006] FIG. 1A is a perspective view of one particular embodiment of inner
and outer molds for manufacturing one specific embodiment of a slip
member.

[0007] FIG. 1B is a perspective view of another particular embodiment of
inner and outer molds for manufacturing another specific embodiment of a
slip member.

[0008] FIG. 2 is a cross-sectional view of the inner and outer molds shown
in FIG. 1A showing the body material and hard material elements disposed
within the inner and outer molds for the manufacture of one specific
embodiment of a slip member.

[0009]FIG. 3 is a cross-sectional view of the inner mold, the outer mold,
the slip member body, and the hard material elements shown in FIG. 2
taken along line 3-3.

[0010]FIG. 4A is a partial perspective view of a slip member after
removal of the inner and outer molds and cutting along the dotted lines
shown in FIG. 3.

[0011] FIG. 4B is a cross-sectional view of one specific embodiment of a
slip member.

[0012]FIG. 5 is a horizontal cross-sectional view of the inner mold, the
outer mold, the slip member body, and the hard material elements during
manufacturing of another specific embodiment of a slip member.

[0013]FIG. 6 is a vertical cross-sectional view of the inner mold, outer
mold, the slip member body, and the hard material elements during
manufacturing of an additional specific embodiment of a slip member.

[0014] FIG. 7A is a partial vertical cross-sectional view of the inner
mold, the outer mold, the slip member body, and the hard material
elements during manufacturing of still another specific embodiment of a
slip member.

[0015] FIG. 7B is a partial vertical cross-sectional view of the inner
mold, the outer mold, the slip member body, and the hard material
elements during manufacturing of yet another specific embodiment of a
slip member.

[0016]FIG. 8 is a cross-sectional view of six hard material elements each
having a different cross-section.

[0017] While the invention will be described in connection with the
preferred embodiments, it will be understood that it is not intended to
limit the invention to that embodiment. On the contrary, it is intended
to cover all alternatives, modifications, and equivalents, as may be
included within the spirit and scope of the invention as defined by the
appended claims.

DETAILED DESCRIPTION OF INVENTION

[0018] Referring now to the Figures, in the manufacturing of various slip
members, inner mold 10 is disposed within outer mold 20. Preferably,
inner mold 10 is disposed concentric with outer mold 20. Inner mold 10
comprises upper end 11, lower end 12, outer wall surface 13, and inner
wall surface 14. Apertures 16 are disposed between and in fluid
communication with outer wall surface 13 and inner wall surface 14. As
shown in the FIGS. 1A, apertures 16 are circular shaped. However, it is
to be understood that apertures 16 can comprise any shape desired or
necessary for receiving hard material elements 30 for preparing the slip
members.

[0020] Apertures 16 are aligned with apertures 26 so that hard material
elements 30 (shown for example in FIG. 2) can be inserted through both
apertures 16 and apertures 26. Although apertures 16 and 26 are shown in
complete alignment with each other in FIGS. 1A, 1B, and 2, it is to be
understood that apertures 16, 26 are not required to be in complete
alignment. In addition, although apertures 16 and 26 are shown as having
the same dimensions, e.g., circumferences and diameters, in FIGS. 1A, 1B,
and 2, it is to be understood that apertures 16, 26 are not required to
have identical dimensions.

[0021] In comparison to FIG. 1A, apertures 16, 26 shown in FIG. 1B are
more spread out than apertures 16, 26 in FIG. 1A. Thus, slip members
formed using inner mold 10 and outer mold 20 shown in FIG. 1B will have
less hard material elements 30 per square area. In other words, the
density of hard material elements 30 in the slip member formed using
inner and outer molds 10, 20 shown in FIG. 1B is less than the density of
hard material elements 30 in the slip member formed using inner and outer
molds 10, 20 shown in FIG. 1A.

[0022] After disposing inner mold 10 within outer mold 20, hard material
elements 30 are disposed through apertures 16, 26. Hard material elements
30 comprise first end 31 and second end 32, and first outer wall surface
33 and second outer wall surface 34 when shown in cross-section such as
in FIGS. 2, 3, 5, 6. As shown in FIGS. 2-3, hard material elements 30 are
solid. Hard material elements 30, however, are not required to be solid.
Instead, as shown in FIGS. 5, 6, 7A, 7B, and 8, hard material elements 30
can include bore 36, thereby reducing the weight of the hard material
element 30 and, thus, the weight of the slip member formed by such hard
material elements 30.

[0023] Hard material elements 30 are formed from a metal, carbide, or
ceramic material, sometimes referred to herein as the "element material."
The element material is harder compared to the material forming body 50
of the slip member, sometimes referred to herein in as the "body
material." The body material can comprise a castable material such as a
resin or composite material. Examples of such resins or composite
materials include epoxy resin polymers.

[0024] Hard material elements 30 can be disposed through apertures 16, 26
so that at least one end of hard material element 30 extends outward from
either outer wall surface 23 of outer mold 20 or inner wall surface 14 of
inner mold. As shown in FIG. 2, first and second ends 31, 32 of hard
material element 30 extend outward from outer wall surface 23 and inner
wall surface 14, respectively. Extension of hard material elements 30
outward from outer wall surface 23 and/or inner wall surface 14 permits
formation of a gripping member using the extended portion of hard
material element 30. The gripping member facilitates engagement of the
slip member to a surface such as the inner wall of a casing disposed in a
well. Extension of first end 31 and second end 32 outwardly from outer
wall surface 23 and inner wall surface 14, respectively, permits
construction of a slip member that can be used on a downhole tool with
either an inner wall of the slip member comprising the gripping member or
an outer wall surface of the slip comprising the gripping member.

[0025] Referring to FIGS. 2-3, hard material elements 30 are disposed
through apertures 16, 26 such that axis 17 of each hard material element
30 is disposed an angle 19 to axis 18 of inner and outer molds 10, 20. As
shown in FIG. 2, angle 19 is 90 degrees so that each hard material
element 30 is disposed perpendicular to axis 19. As discussed in greater
detail below, angle 19 is not required to be 90 degrees.

[0026] After disposing hard material elements 30 through apertures 16, 26,
a body material, such as an epoxy resin polymer, is pored into the space
between inner and outer molds 10, 20, thereby forming body 50 by
capturing each hard material element 30 within body 50. Thus, the body
material facilitates formation of body 50 of the slip member.

[0027] After the body material has set, inner and outer molds 10, 20 are
removed to provide a cylindrically-shaped tubular body 50 having one or
more hard material elements 30 extended through the body material. This
tubular body can be cut into an initial slip-shaped member such as one or
more wedges, such as along the dotted lines in FIG. 3, to provide the
wedge partially shown in FIG. 4A. Thereafter, the initial slip-shaped
member, e.g., a wedge, can be shaped using grinders or other tools to
provide a slip member such as shown in FIG. 4B.

[0028] As illustrated in FIG. 4B, one particular slip member 60 comprises
upper end 61, lower end 62, first surface 63, and second surface 64. As
shown in FIG. 4B, first surface 63 comprises a plurality of gripping
members 39 shaped at one end of each of hard material elements 30 and,
therefore, first surface 63 comprises a gripping surface. Due to the
location of hard material elements 30 within body 50, a cross-sectional
view, such as shown in FIG. 4B, shows alternating layers of body 50 and
hard material elements 30.

[0029] After shaping the wedge, slip member 60 can be disposed on a
downhole tool to facilitate securing the downhole tool within a well,
such as within a cased wellbore.

[0030] Referring now to FIG. 5, in another embodiment, hard material
element 30 comprises first and second outer wall surfaces 33, 34 that are
tapered from first end 31 to second end 32. In addition, hard material
element 30 comprises bore 36 which reduces the weight of each hard
material element 30 and facilitates breaking up hard material element 30
during milling operations to remove the slip member from the well. Other
than this change in the shape and design of hard material element 30, the
slip members can be manufactured in a similar manner as described above.

[0031] As illustrated in FIG. 6, each hard material element 30 in this
embodiment is disposed through apertures 16, 26 at angle 19 where angle
19 is not equal to 90 degrees. Instead, angle 19 is in the range from 0
degrees to 90 degrees. In one particular embodiment angle 19 is in the
range from 10 to 75 degrees. Other than this change in the shape and
design of hard material element 30, the slip members can be manufactured
in a similar manner as described above.

[0032] Referring now to FIG. 7A, in another embodiment, hard material
element 30 comprises first portion 41, second portion 42, and third
portion 43 with first portion 41 being disposed such that it is in
contact with both second and third portions 42, 43. This "stacking"
arrangement provides greater strength to hard material element 30, yet
still facilitate easy milling operations to remove the slip member from
the well. As shown in FIG. 7A, second and third portions 42, 43 are
disposed through inner mold 10 and first portion 41 is disposed through
outer mold 20. It is to be understood, however, that first portion 41 can
be disposed through inner mold 10 and second and third portions 42, 43
can be disposed through outer mold 20. Other than this change in the
shape and design of hard material element 30, the slip members can be
manufactured in a similar manner as described above.

[0033] FIG. 7B shows an additional embodiment in which outer wall surfaces
33, 34 of hard material element 30 comprise recess 38 disposed between
first and second ends 31, 32. Recess 38 is preferably disposed
approximately half-way between first and second ends 31, 32. Recess 38
facilitates breaking up hard material element 30 during milling
operations to remove the slip member from the well. Other than this
change in the shape and design of hard material element 30, the slip
members can be manufactured in a similar manner as described above.

[0034] Referring now to FIG. 8, hard material element 30 is shown as
having several different cross-sectional shapes such as, from left to
right, hexagonal-shaped with bore 36, square-shaped with bore 36, solid
square-shaped, circular-shaped with bore 36, sold circular-shaped, and
triangular-shaped with bore 36.

[0035] It is to be understood that the invention is not limited to the
exact details of construction, operation, exact materials, or embodiments
shown and described, as modifications and equivalents will be apparent to
one skilled in the art. For example, the element material is not required
to be a metal, carbide, or ceramic material and the body material is not
required to be a composite or resin material. All that is required is
that the element material be harder than the body material. Moreover, the
shapes and dimensions of the hard material elements are not limited to
those disclosed herein. Nor are the shapes and dimensions of the
apertures through the inner and outer molds limited to those disclosed
herein. In addition, there is no requirement that the inner mold be
disposed concentrically with the outer mold. Instead, the inner mold
could be disposed eccentrically so that one wedge can be cut from the
tubular body that is thinner than another wedge. As a result, two slip
members having different thicknesses can be manufactured from a single
tubular body. Further, both ends of the hard material element are not
required to extend outwardly from the body during manufacture. Instead,
one end of the hard material element can be flush with the first or
second surface of the tubular body so that one end is not required to be
ground away during shaping of the slip member. Additionally, in
embodiments in which the hard material elements include a bore, the ends
of the bore can be masked or sealed to provide a chamber within the hard
material elements. Moreover, the outer wall surfaces of the hard material
elements can be roughened or polished to facilitate bonding the body
material to the hard material element. Further, the first and second
outer wall surfaces can be tapered from the second end toward the first
end instead of vice versa. Accordingly, the invention is therefore to be
limited only by the scope of the appended claims.